Various assembly proposals have been made for securing automotive ignition cables within spark plug boots. For simplicity, push-to-seat and pull-to-seat assembly procedures are commonly used, in which, in a first assembly step, the ignition cable is pushed or pulled through the boot until a cable end terminal contacts a forward or a backward stop within the boot. The top of the boot is then glued to the cable in a second assembly step, to prevent reverse motion of the cable through the boot. The second assembly step adds cost and complexity to the assembly procedure.
To avoid such second step, a twist-to-lock assembly procedure has been proposed in which the ignition cable is, in a first step, inserted through the boot until a cable end terminal contacts a backward stop within the boot and then, in a second step, the boot is rotated relative to the ignition cable a predetermined rotational displacement to a position providing for bi-directional locking between the cable and the boot. Such second step again adds cost and complexity to the overall procedure and requires a departure from standard assembly procedures, reducing procedure efficiency and ease of assembly. Additionally, such proposed twist-to-lock procedure is subject to reliability shortcomings. A locking position requires proper rotational displacement. The boot can only be rotated when then cable is substantially engaged with the backstop and then does not lock until the proper degree of rotation is provided and maintained.
It would therefore be desirable to provide for bi-directional position assurance of an ignition cable and spark plug boot through standard assembly procedures with a minimum number of steps and with high reliability.